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NAME

       FileCheck - Flexible pattern matching file verifier

SYNOPSIS

       FileCheck match-filename [–check-prefix=XXX] [–strict-whitespace]

DESCRIPTION

       FileCheck reads two files (one from standard input, and one specified on the command line)
       and uses one to verify the other.  This behavior is particularly useful for the testsuite,
       which  wants  to  verify  that  the  output  of some tool (e.g. llc) contains the expected
       information (for example, a movsd from esp or whatever is interesting).  This  is  similar
       to using grep, but it is optimized for matching multiple different inputs in one file in a
       specific order.

       The match-filename file specifies the file that contains the patterns to match.  The  file
       to verify is read from standard input unless the --input-file option is used.

OPTIONS

       -help  Print a summary of command line options.

       --check-prefix prefix
              FileCheck  searches  the  contents  of  match-filename  for  patterns to match.  By
              default, these patterns are prefixed  with  “CHECK:”.   If  you’d  like  to  use  a
              different  prefix  (e.g. because the same input file is checking multiple different
              tool or options), the --check-prefix argument allows you to  specify  one  or  more
              prefixes  to  match.  Multiple prefixes are useful for tests which might change for
              different run options, but most lines remain the same.

       --check-prefixes prefix1,prefix2,...
              An alias of --check-prefix that allows multiple prefixes to be specified as a comma
              separated list.

       --input-file filename
              File to check (defaults to stdin).

       --match-full-lines
              By  default,  FileCheck  allows  matches  of  anywhere  on a line. This option will
              require all positive  matches  to  cover  an  entire  line.  Leading  and  trailing
              whitespace  is  ignored,  unless  --strict-whitespace  is  also  specified.  (Note:
              negative matches from CHECK-NOT are not affected by this option!)

              Passing this option is equivalent to inserting {{^ *}} or {{^}} before, and {{ *$}}
              or {{$}} after every positive check pattern.

       --strict-whitespace
              By  default,  FileCheck canonicalizes input horizontal whitespace (spaces and tabs)
              which causes it to ignore these differences  (a  space  will  match  a  tab).   The
              --strict-whitespace  argument  disables  this  behavior.  End-of-line sequences are
              canonicalized to UNIX-style \n in all modes.

       --implicit-check-not check-pattern
              Adds implicit negative checks for the specified patterns between  positive  checks.
              The option allows writing stricter tests without stuffing them with CHECK-NOTs.

              For  example, “--implicit-check-not warning:” can be useful when testing diagnostic
              messages from tools that don’t have an option similar to clang -verify.  With  this
              option  FileCheck  will  verify that input does not contain warnings not covered by
              any CHECK: patterns.

       -version
              Show the version number of this program.

EXIT STATUS

       If FileCheck verifies that the file matches  the  expected  contents,  it  exits  with  0.
       Otherwise, if not, or if an error occurs, it will exit with a non-zero value.

TUTORIAL

       FileCheck  is  typically used from LLVM regression tests, being invoked on the RUN line of
       the test.  A simple example of using FileCheck from a RUN line looks like this:

          ; RUN: llvm-as < %s | llc -march=x86-64 | FileCheck %s

       This syntax says to pipe the current file (“%s”) into llvm-as, pipe that  into  llc,  then
       pipe  the  output  of llc into FileCheck.  This means that FileCheck will be verifying its
       standard input (the llc output) against the filename argument specified (the original  .ll
       file  specified  by  “%s”).  To see how this works, let’s look at the rest of the .ll file
       (after the RUN line):

          define void @sub1(i32* %p, i32 %v) {
          entry:
          ; CHECK: sub1:
          ; CHECK: subl
                  %0 = tail call i32 @llvm.atomic.load.sub.i32.p0i32(i32* %p, i32 %v)
                  ret void
          }

          define void @inc4(i64* %p) {
          entry:
          ; CHECK: inc4:
          ; CHECK: incq
                  %0 = tail call i64 @llvm.atomic.load.add.i64.p0i64(i64* %p, i64 1)
                  ret void
          }

       Here you can see some “CHECK:” lines specified in comments.  Now you can see how the  file
       is  piped  into  llvm-as,  then llc, and the machine code output is what we are verifying.
       FileCheck checks the machine code output to verify that it matches what the “CHECK:” lines
       specify.

       The syntax of the “CHECK:” lines is very simple: they are fixed strings that must occur in
       order.  FileCheck defaults to ignoring horizontal whitespace differences (e.g. a space  is
       allowed  to  match  a tab) but otherwise, the contents of the “CHECK:” line is required to
       match some thing in the test file exactly.

       One nice thing about FileCheck (compared to grep) is that it  allows  merging  test  cases
       together  into  logical  groups.   For example, because the test above is checking for the
       “sub1:” and “inc4:” labels, it will not match unless there is a “subl”  in  between  those
       labels.   If  it  existed  somewhere  else  in the file, that would not count: “grep subl”
       matches if “subl” exists anywhere in the file.

   The FileCheck -check-prefix option
       The FileCheck -check-prefix option allows multiple test configurations to be  driven  from
       one  .ll  file.   This  is  useful  in  many circumstances, for example, testing different
       architectural variants with llc.  Here’s a simple example:

          ; RUN: llvm-as < %s | llc -mtriple=i686-apple-darwin9 -mattr=sse41 \
          ; RUN:              | FileCheck %s -check-prefix=X32
          ; RUN: llvm-as < %s | llc -mtriple=x86_64-apple-darwin9 -mattr=sse41 \
          ; RUN:              | FileCheck %s -check-prefix=X64

          define <4 x i32> @pinsrd_1(i32 %s, <4 x i32> %tmp) nounwind {
                  %tmp1 = insertelement <4 x i32>; %tmp, i32 %s, i32 1
                  ret <4 x i32> %tmp1
          ; X32: pinsrd_1:
          ; X32:    pinsrd $1, 4(%esp), %xmm0

          ; X64: pinsrd_1:
          ; X64:    pinsrd $1, %edi, %xmm0
          }

       In this case, we’re testing that we get the expected code generation with both 32-bit  and
       64-bit code generation.

   The “CHECK-NEXT:” directive
       Sometimes  you want to match lines and would like to verify that matches happen on exactly
       consecutive lines with no other lines in between them.  In this case, you can use “CHECK:”
       and  “CHECK-NEXT:”  directives  to  specify this.  If you specified a custom check prefix,
       just use “<PREFIX>-NEXT:”.  For example, something like this works as you’d expect:

          define void @t2(<2 x double>* %r, <2 x double>* %A, double %B) {
               %tmp3 = load <2 x double>* %A, align 16
               %tmp7 = insertelement <2 x double> undef, double %B, i32 0
               %tmp9 = shufflevector <2 x double> %tmp3,
                                      <2 x double> %tmp7,
                                      <2 x i32> < i32 0, i32 2 >
               store <2 x double> %tmp9, <2 x double>* %r, align 16
               ret void

          ; CHECK:          t2:
          ; CHECK:             movl    8(%esp), %eax
          ; CHECK-NEXT:        movapd  (%eax), %xmm0
          ; CHECK-NEXT:        movhpd  12(%esp), %xmm0
          ; CHECK-NEXT:        movl    4(%esp), %eax
          ; CHECK-NEXT:        movapd  %xmm0, (%eax)
          ; CHECK-NEXT:        ret
          }

       “CHECK-NEXT:” directives reject the input unless there is exactly one newline  between  it
       and the previous directive.  A “CHECK-NEXT:” cannot be the first directive in a file.

   The “CHECK-SAME:” directive
       Sometimes you want to match lines and would like to verify that matches happen on the same
       line as the previous match.   In  this  case,  you  can  use  “CHECK:”  and  “CHECK-SAME:”
       directives   to  specify  this.   If  you  specified  a  custom  check  prefix,  just  use
       “<PREFIX>-SAME:”.

       “CHECK-SAME:” is particularly powerful in conjunction with “CHECK-NOT:” (described below).

       For example, the following works like you’d expect:

          !0 = !DILocation(line: 5, scope: !1, inlinedAt: !2)

          ; CHECK:       !DILocation(line: 5,
          ; CHECK-NOT:               column:
          ; CHECK-SAME:              scope: ![[SCOPE:[0-9]+]]

       “CHECK-SAME:” directives reject the input if there are any newlines  between  it  and  the
       previous directive.  A “CHECK-SAME:” cannot be the first directive in a file.

   The “CHECK-NOT:” directive
       The  “CHECK-NOT:”  directive  is  used  to  verify that a string doesn’t occur between two
       matches (or before the first match, or after the last match).  For example, to verify that
       a load is removed by a transformation, a test like this can be used:

          define i8 @coerce_offset0(i32 %V, i32* %P) {
            store i32 %V, i32* %P

            %P2 = bitcast i32* %P to i8*
            %P3 = getelementptr i8* %P2, i32 2

            %A = load i8* %P3
            ret i8 %A
          ; CHECK: @coerce_offset0
          ; CHECK-NOT: load
          ; CHECK: ret i8
          }

   The “CHECK-DAG:” directive
       If  it’s  necessary  to  match  strings  that  don’t occur in a strictly sequential order,
       “CHECK-DAG:” could be used to verify them between two matches (or before the first  match,
       or  after the last match). For example, clang emits vtable globals in reverse order. Using
       CHECK-DAG:, we can keep the checks in the natural order:

          // RUN: %clang_cc1 %s -emit-llvm -o - | FileCheck %s

          struct Foo { virtual void method(); };
          Foo f;  // emit vtable
          // CHECK-DAG: @_ZTV3Foo =

          struct Bar { virtual void method(); };
          Bar b;
          // CHECK-DAG: @_ZTV3Bar =

       CHECK-NOT: directives could be mixed with CHECK-DAG: directives to exclude strings between
       the  surrounding CHECK-DAG: directives. As a result, the surrounding CHECK-DAG: directives
       cannot be reordered, i.e. all occurrences matching CHECK-DAG: before CHECK-NOT:  must  not
       fall behind occurrences matching CHECK-DAG: after CHECK-NOT:. For example,

          ; CHECK-DAG: BEFORE
          ; CHECK-NOT: NOT
          ; CHECK-DAG: AFTER

       This case will reject input strings where BEFORE occurs after AFTER.

       With  captured variables, CHECK-DAG: is able to match valid topological orderings of a DAG
       with edges from the definition of a variable to its use.  It’s  useful,  e.g.,  when  your
       test  cases  need  to match different output sequences from the instruction scheduler. For
       example,

          ; CHECK-DAG: add [[REG1:r[0-9]+]], r1, r2
          ; CHECK-DAG: add [[REG2:r[0-9]+]], r3, r4
          ; CHECK:     mul r5, [[REG1]], [[REG2]]

       In this case, any order of that two add instructions will be allowed.

       If you are defining and using variables in the same CHECK-DAG: block, be  aware  that  the
       definition rule can match after its use.

       So, for instance, the code below will pass:

          ; CHECK-DAG: vmov.32 [[REG2:d[0-9]+]][0]
          ; CHECK-DAG: vmov.32 [[REG2]][1]
          vmov.32 d0[1]
          vmov.32 d0[0]

       While this other code, will not:

          ; CHECK-DAG: vmov.32 [[REG2:d[0-9]+]][0]
          ; CHECK-DAG: vmov.32 [[REG2]][1]
          vmov.32 d1[1]
          vmov.32 d0[0]

       While  this  can  be  very  useful,  it’s  also dangerous, because in the case of register
       sequence, you must have a strong order (read before write, copy before use, etc).  If  the
       definition  your  test is looking for doesn’t match (because of a bug in the compiler), it
       may match further away from the use, and mask real bugs away.

       In those cases, to enforce the order, use a non-DAG directive between DAG-blocks.

   The “CHECK-LABEL:” directive
       Sometimes in a file containing multiple tests divided into logical  blocks,  one  or  more
       CHECK:  directives  may inadvertently succeed by matching lines in a later block. While an
       error will usually eventually be generated, the check flagged as causing the error may not
       actually bear any relationship to the actual source of the problem.

       In order to produce better error messages in these cases, the “CHECK-LABEL:” directive can
       be used. It is treated identically to a normal CHECK directive except that FileCheck makes
       an  additional  assumption  that a line matched by the directive cannot also be matched by
       any other check present  in  match-filename;  this  is  intended  to  be  used  for  lines
       containing  labels  or other unique identifiers. Conceptually, the presence of CHECK-LABEL
       divides the input stream into separate blocks, each of which is  processed  independently,
       preventing a CHECK: directive in one block matching a line in another block.  For example,

          define %struct.C* @C_ctor_base(%struct.C* %this, i32 %x) {
          entry:
          ; CHECK-LABEL: C_ctor_base:
          ; CHECK: mov [[SAVETHIS:r[0-9]+]], r0
          ; CHECK: bl A_ctor_base
          ; CHECK: mov r0, [[SAVETHIS]]
            %0 = bitcast %struct.C* %this to %struct.A*
            %call = tail call %struct.A* @A_ctor_base(%struct.A* %0)
            %1 = bitcast %struct.C* %this to %struct.B*
            %call2 = tail call %struct.B* @B_ctor_base(%struct.B* %1, i32 %x)
            ret %struct.C* %this
          }

          define %struct.D* @D_ctor_base(%struct.D* %this, i32 %x) {
          entry:
          ; CHECK-LABEL: D_ctor_base:

       The  use  of CHECK-LABEL: directives in this case ensures that the three CHECK: directives
       only accept lines corresponding to the body of the  @C_ctor_base  function,  even  if  the
       patterns  match  lines  found later in the file. Furthermore, if one of these three CHECK:
       directives fail, FileCheck will recover by continuing to the next block, allowing multiple
       test failures to be detected in a single invocation.

       There  is  no  requirement that CHECK-LABEL: directives contain strings that correspond to
       actual syntactic labels in a source or output language: they must simply uniquely match  a
       single line in the file being verified.

       CHECK-LABEL: directives cannot contain variable definitions or uses.

   FileCheck Pattern Matching Syntax
       All  FileCheck  directives  take  a  pattern  to match.  For most uses of FileCheck, fixed
       string matching is perfectly sufficient.   For  some  things,  a  more  flexible  form  of
       matching is desired.  To support this, FileCheck allows you to specify regular expressions
       in matching strings, surrounded by double braces: {{yourregex}}.  Because we want  to  use
       fixed string matching for a majority of what we do, FileCheck has been designed to support
       mixing and matching fixed string matching with regular expressions.  This  allows  you  to
       write things like this:

          ; CHECK: movhpd      {{[0-9]+}}(%esp), {{%xmm[0-7]}}

       In  this case, any offset from the ESP register will be allowed, and any xmm register will
       be allowed.

       Because regular expressions are enclosed with double braces, they are  visually  distinct,
       and  you don’t need to use escape characters within the double braces like you would in C.
       In the rare case that you want to match double braces explicitly from the input,  you  can
       use something ugly like {{[{][{]}} as your pattern.

   FileCheck Variables
       It  is  often  useful to match a pattern and then verify that it occurs again later in the
       file.  For codegen tests, this can be useful to allow any register, but verify  that  that
       register  is  used consistently later.  To do this, FileCheck allows named variables to be
       defined and substituted into patterns.  Here is a simple example:

          ; CHECK: test5:
          ; CHECK:    notw     [[REGISTER:%[a-z]+]]
          ; CHECK:    andw     {{.*}}[[REGISTER]]

       The first check line matches a regex %[a-z]+ and captures it into the  variable  REGISTER.
       The  second  line  verifies that whatever is in REGISTER occurs later in the file after an
       “andw”.  FileCheck variable references are always contained in  [[  ]]  pairs,  and  their
       names  can  be  formed  with the regex [a-zA-Z][a-zA-Z0-9]*.  If a colon follows the name,
       then it is a definition of the variable; otherwise, it is a use.

       FileCheck variables can be defined multiple times, and uses always get the  latest  value.
       Variables can also be used later on the same line they were defined on. For example:

          ; CHECK: op [[REG:r[0-9]+]], [[REG]]

       Can  be  useful  if  you  want  the operands of op to be the same register, and don’t care
       exactly which register it is.

   FileCheck Expressions
       Sometimes there’s a need to verify output which refers line numbers  of  the  match  file,
       e.g.  when testing compiler diagnostics.  This introduces a certain fragility of the match
       file structure, as “CHECK:” lines contain absolute line numbers in the  same  file,  which
       have to be updated whenever line numbers change due to text addition or deletion.

       To   support   this   case,   FileCheck   allows   using   [[@LINE]],  [[@LINE+<offset>]],
       [[@LINE-<offset>]] expressions in patterns. These expressions expand to a  number  of  the
       line where a pattern is located (with an optional integer offset).

       This  way match patterns can be put near the relevant test lines and include relative line
       number references, for example:

          // CHECK: test.cpp:[[@LINE+4]]:6: error: expected ';' after top level declarator
          // CHECK-NEXT: {{^int a}}
          // CHECK-NEXT: {{^     \^}}
          // CHECK-NEXT: {{^     ;}}
          int a

   Matching Newline Characters
       To match newline characters in regular expressions the character class [[:space:]] can  be
       used. For example, the following pattern:

          // CHECK: DW_AT_location [DW_FORM_sec_offset] ([[DLOC:0x[0-9a-f]+]]){{[[:space:]].*}}"intd"

       matches output of the form (from llvm-dwarfdump):

          DW_AT_location [DW_FORM_sec_offset]   (0x00000233)
          DW_AT_name [DW_FORM_strp]  ( .debug_str[0x000000c9] = "intd")

       letting us set the FileCheck variable DLOC to the desired value 0x00000233, extracted from
       the line immediately preceding “intd”.

AUTHOR

       Maintained by The LLVM Team (http://llvm.org/).

COPYRIGHT

       2003-2018, LLVM Project